Home

About

Advanced Search

Browse by Discipline

Scientific Societies

E-print Alerts

Add E-prints

E-print Network
FAQHELPSITE MAPCONTACT US


  Advanced Search  

 
Mon. Not. R. Astron. Soc. 339, 133147 (2003) The instability of fast shocks in molecular clouds
 

Summary: Mon. Not. R. Astron. Soc. 339, 133147 (2003)
The instability of fast shocks in molecular clouds
Michael D. Smith and Alexander Rosen
Armagh Observatory, College Hill, Armagh BT61 9DG
Accepted 2002 October 7. Received 2002 September 2; in original form 2001 October 19
ABSTRACT
We report on the discovery that moderately fast shocks in dense molecular clouds with low
transverse magnetic fields are likely to be unstable. The instability is triggered by the promoted
cooling that results from the formation of carbon monoxide and water molecules in an extended
warm shock section. Numerical methods are employed to demonstrate that, in the absence of
magnetic fields, the instability regime is restricted to densities above n0 = 104
cm-3
, velocities
between 3070 km s-1
, and O or C abundances above 10-4
, so that cooling from reforming
molecules dominates in the warm gas without being suppressed by ultraviolet dissociation. The
result is either a quasi-periodic or chaotic collapse and re-establishment of the warm shock
layer on a typical time-scale of 106
cm-3

  

Source: Armagh Observatory

 

Collections: Physics